Results of previous studies suggested that the vestibular mediated postural instability observed in astronauts upon return to earth from orbital spaceflight may be exacerbated by an increased weighting of visual inputs for spatial orientation and control of movement. This study was performed to better understand the roles of visual and somatosensory contributions to recovery of normal sensori-motor postural control in returning astronauts. Preflight and postflight, 23 astronaut volunteers were presented randomly with three trials of six sensory organization test (SOT) conditions in the EquiTest system test battery. Sagittal plane center-of-gravity (COG) excursions computed from ground reaction forces were significantly higher on landing day than preflight for those test conditions presenting sway-referenced visual and/or somatosensory orientation cues. The ratio of summed peak-to-peak COG sway amplitudes on the two sway-referenced vision tests (SOTs 3 + 6) compared to the two eyes closed tests (SOTs 2 + 5) was increased on landing day, indicating an increased reliance on visual orientation cues for postural control. The ratio of peak-to-peak COG excursions on sway-referenced surfaces (SOTs 4, 5 & 6) to an earth fixed support surfaces (SOTs 1, 2 & 3) increased even more after landing suggesting primary reliance on somatosensory orientation cues for recovery of postflight postural stability. Readaptation to sway-referenced support surfaces took longer than readaptation to sway-referenced vision. The increased reliance on visual and somatosensory inputs disappeared in all astronauts 4-8 days following return to earth.


    Access

    Access via TIB

    Check availability in my library


    Export, share and cite



    Title :

    Vestibular plasticity following orbital spaceflight: recovery from postflight postural instability


    Contributors:


    Publication date :

    1995-01-01



    Type of media :

    Miscellaneous


    Type of material :

    No indication


    Language :

    English




    The Effects of Long-Duration Spaceflight on Postflight Terrestrial Locomotion

    Bloomberg, J. J. / Mulavara, A. P. / McDonald, P. V. et al. | NTRS | 1999



    Neuro-Vestibular Examination During and Following Spaceflight (Vestibular Health)

    T. R. Macaulay / S. J. Wood / M. F. Reschke et al. | NTIS | 2023